Device for passing a conductor through the cover of an electrical precipitation apparatus

ABSTRACT

Improved lead-in device passing a conductor through the cover of an electrical precipitation apparatus down to its spray system. The improved device is characterized in that a porous insulator is used as the insulator and a gas-tight insulating cylinder concentrically surrounds the porous insulator. The device is further fitted with a tubular gas inlet opening into the porous insulating cylinder. The upper and lower ends of the insulator and the insulating cylinder, respectively, are connected together by annular metal plates so as to form a space therebetween, and the space is occupied by a sealing gas maintained at a relatively higher pressure than that prevailing inside the electrical precipitation apparatus.

[ Aug. 28, 1973 United States Patent [191 Queck et a1.

[56] References Cited UNITED STATES PATENTS 1 1 DEVICE FOR PASSING ACONDUCTOR THROUGH THE COVER OF AN 3,595,983 7/1971 Muller et a1. 174/315ELECTRICAL PRECIPITATION APPARATUS Primary Examiner-Laramie E. AskinAttorney-Arthur G. Connolly, Jacob C. Kellem et knapsackAktiengeselischnft,

[57] ABSTRACT Improved lead-in device passing a conductor through thecover of an electrical precipitation apparatus down [73] Assignee:

Knapsack near Cologne, Germany Aug. 7, 1972.

[22] Filed:

to its spray system. The improved device is character- PP 2731569 izedin that a porous insulator is used as the insulator [30] and a gas-tightinsulating cylinder concentrically sur- Fords Applicamn Pmmty Datarounds the porous insulator. The device is further fitted Aug. 9, 1971Germany................... P 21 39 824.3

with a tubular gas inlet opening into the porous insulating cylinder.The upper and lower ends of the insulator 174/31 R,

174/21 1 and the insulating cylinder, respectively, are connectedtogether by annular metal plates so as to form a space Bose 3/34 Holt17,26 therebetween, and the space is occupied by a sealing Field of gasmaintained at a relatively higher pressure than that prevailing insidethe electrical precipitation apparatus.

[51] Int. [58] 174/11 BB, 12 RH, 174/14 BH,15 BB, 16 BH,17.06, 18, 31 R4 Claims, 1 Drawing Figure Hig DEVICE FOR PASSING A CONDUCTOR THROUGHTHE COVER OF AN ELECTRICAL PRECIPITATION APPARATUS The present inventionprovides a device passing a conductor through the cover of an electricalprecipitation apparatus.

US. Pat. No. 3,595,983 describes a device for passing a conductorthrough the cover of an electrical precipitation apparatus down to itselectrode system, the conductor being concentrically surrounded by aduct arranged to run through the cover of the electrical precipitationapparatus to the interior of the said apparatus, wherein the conductoris surrounded near its supper end by an insulator; the said insulatorbeing positioned above the cover of the said apparatus so as to beradially spaced from the conductor, wherein an insulating bush issecured to the conductor at a position near the said insulator, andwherein the said insulating bush is surrounded by a barrier disk so asto leave a slit between itself and the barrier disk, the space leftabove the barrier disk being occupied by a sealing gas maintained underoverpressure with respect to the pressure prevailing inside theelectrical precipitation apparatus.

Upon the occurrence of undue pressure variations in the electricalprecipitation apparatus, the sealing gas present in the duct iscompressed and dust-containing gas can escape from the electricalprecipitation apparatus and affect the insulating elements (insulatingbush,

barrier disk, insulator) with the resultant formation of electricallyconducting material on said insulating elements. This in turn may resultin electrical flashing over. The present invention now provides animproved device for passing a conductor through the cover of anelectrical precipitation apparatus down to its electrode system,characterized in that the conductor passes centrally through a porousinsulator; the said insulator being concentrically surrounded by agas-tight insulating cylinder, the said insulating cylinder, beingprovided with a tubular gas inlet opening thereinto, the upper and lowerends of the said insulator and the said insulating cylinder,respectively, being connected together by annular metal plates so as toform a space therebetween, said space being occupied by a sealing gasdelivered through said tubular gas inlet and maintained underoverpressure with respect to the pressure prevailing inside theelectrical precipitation apparatus.

Further preferred features of the device of the present invention, whichcan be used singly or in combination, provide;

a. for the said insulator to be made of porous polytetrafluoroethylene;b. for the porous polytetrafluoroethylene to have pores with a diameterbetween 40 and 60 microns, preferably 50 microns.

The invention will now be described with reference to the accompanyingdrawing, of which the single FlG- URE is a side elevational view of thedevice of the present invention.

As can be seen, a conductor 1, i.e., the upper portion thereof, issurrounded by a bellows 8, of which the upper end is connected toconductor 1, e.g., by bolts, and of which the lower end is secured to anannular metal plate 9. Further secured to annular metal plate 9 are aporous insulator 3 and an insulating cylinder 4 concentricallysurrounding porous insulator 3. A tubular gas inlet 5 opens intoinsulating cylinder 4. The lower ends of porous insulator 3 andinsulating cylinder 4 are connected together by means of an annularmetal plate 10 so as to form an annular space 6 between and bounded byporous insulator 3, annular metal plates (9, l0) and insulating cylinder4. Placed below metal plate 10 is a cylindrical connection 11 andsecured thereto are a cover 7 of a sealing cup and its associated divinghell 2.

Sealing gas, which is introduced under a pressure of substantially 1atmosphere (gauge) into space 6, through tubular gas inlet 5, flowsthrough the pores of porous insulator 3 and produces a continuallyrenewing gas film on the surface of porous insulator 3 facingconductor 1. As a result, electrically conducting material is preventedfrom depositing on porous insulator 3.

The consumption of sealing gas in the device of the present invention isvery low, due to the dimensions selected for the pores (50 microns, forexample).

We claim:

1. A lead-in device passing a conductor through the cover of anelectrical precipitation apparatus down to its spray system,characterized in that the conductor passes centrally through a porousinsulator; the said insulator being concentrically surrounded by agas-tight insulating cylinder; the said insulating cylinder beingprovided with a tubular gas inlet opening thereinto; the upper and lowerends of the said insulator and the said insulating cylinder,respectively, being connected together by annular metal plates so as toform a space therebetween, and said space being occupied by a sealinggas maintained at a relatively higher pressure than that prevailinginside the electrical precipitation apparatus.

2. The device as claimed in claim 1, wherein the said insulator is madeup of porous polytetrafluoroethylene.

3. The device as claimed in claim 2, wherein the porouspolytetrafluoroethylene has pores with a diameter between 40 and 60microns.

4. The device as claimed in claim 3, wherein the porouspolytetrafluoroethylene has pores with a diameter of 50 microns.

1. A lead-in device passing a conductor through the cover of anelectrical precipitation apparatus down to its spray system,characterized in that the conductor passes centrally through a porousinsulator; the said insulator being concentrically surrounded by agas-tight insulating cylinder; the said insulating cylinder beingprovided with a tubular gas inlet opening thereinto; the upper and lowerends of the said insulator and the said insulating cylinder,respectively, being connected together by annular metal plates so as toform a space therebetween, and said space being occupied by a sealinggas maintained at a relatively higher pressure than that prevailinginside the electrical precipitation apparatus.
 2. The device as claimedin claim 1, wherein the said insulator is made up of porouspolytetrafluoroethylene.
 3. The device as claimed in claim 2, whereinthe porous polytetrafluoroethylene has pores with a diameter between 40and 60 microns.
 4. The device as claimed in claim 3, wherein the porouspolytetrafluoroethylene has pores with a diameter of 50 microns.